A SUMMARY OF LINKAGE RELATIONSHIPS AND A REVISED LINKAGE MAP OF THE CHICKEN

1973 ◽  
Vol 15 (3) ◽  
pp. 553-570 ◽  
Author(s):  
R. J. Etches ◽  
R. O. Hawes

The literature pertaining to linkage relationships in the chicken has been reviewed. A new linkage map is proposed consisting of 13 linkage groups. In cases where nomenclature has been duplicated, new symbols are proposed. A tabular summary of linkage tests which have shown independent segregation is included.

Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 888-895 ◽  
Author(s):  
Bernie May ◽  
Kathrine J. Henley ◽  
Christine G. Fisher ◽  
Daniel J. Royse

Single spore derived Pleurotus spp. isolates from four commercial lines (two P. sapidus, one P. florida, and one P. ostreatus) and from two interspecific hybrids (P. sajor-caju × P. sapidus) were analyzed for single locus and joint segregation of 25 allozyme encoding loci. The two alleles at the individual loci departed significantly in their segregation from a 1:1 Mendelian ratio in 26% of the intraspecific and 29% of the interspecific tests. Six linkage groups were identified as follows: Dia-1 ~ Est-5; Tpi ~ Pgd-2 ~ Skdh; (Fum) ~ Pgm-2 ~ Pgd-1 ~ PepLgg-1 ~ Gr-2; Ndh ~ Gr-1; Np ~ PepGl-1 ~ Aat-2 ~ Pgk ~ Mup; and Gr-4 ~ Mdh-1. The duplicate loci coding for GR, PEP-LGG, PGM, and PGD were both not linked to each other and not part of duplicate linkage groups. Six loci were not shown to be linked to any other loci (Lap, Pgm-1, Ha, Gpi, PepPap, and PepLgg-2), although the latter two loci were only tested against four and five loci, respectively. The first linkage map of 19 allozyme encoding loci for the Pleurotus genome is presented.Key words: Pleurotus, allozymes, linkage map, inheritance, edible fungi.


1993 ◽  
Vol 73 (4) ◽  
pp. 917-926 ◽  
Author(s):  
R. E. Vaillancourt ◽  
A. E. Slinkard

Six new isozymes and three morphological markers were placed on the lentil (Lens culinaris L.) linkage map. The 17 isozymes and 11 morphological markers that were studied formed four linkage groups (I through IV). These linkage groups represent linkage relationships in the cultivated lentil (L. c. ssp. culinaris) and its wild progenitor (L. c. ssp. orientalis). However, in crosses between L. c. ssp. odemensis and other ssp. of L. culinaris, linkage relationships were slightly different. In these crosses markers of linkage groups III and IV showed disturbed segregation and pseudo-linkage. Although wide crosses contain more variability than narrow crosses in lentil, linkage relationships are more difficult to interpret because of the prevalence of disturbed segregation and pseudo-linkage. Key words: Lentil, Lens culinaris, linkage, isozyme, pseudo-linkage


2017 ◽  
Vol 7 (7) ◽  
pp. 2353-2361 ◽  
Author(s):  
Jacob A Tennessen ◽  
Stephanie R Bollmann ◽  
Michael S Blouin

Abstract The aquatic planorbid snail Biomphalaria glabrata is one of the most intensively-studied mollusks due to its role in the transmission of schistosomiasis. Its 916 Mb genome has recently been sequenced and annotated, but it remains poorly assembled. Here, we used targeted capture markers to map over 10,000 B. glabrata scaffolds in a linkage cross of 94 F1 offspring, generating 24 linkage groups (LGs). We added additional scaffolds to these LGs based on linkage disequilibrium (LD) analysis of targeted capture and whole-genome sequences of 96 unrelated snails. Our final linkage map consists of 18,613 scaffolds comprising 515 Mb, representing 56% of the genome and 75% of genic and nonrepetitive regions. There are 18 large (> 10 Mb) LGs, likely representing the expected 18 haploid chromosomes, and > 50% of the genome has been assigned to LGs of at least 17 Mb. Comparisons with other gastropod genomes reveal patterns of synteny and chromosomal rearrangements. Linkage relationships of key immune-relevant genes may help clarify snail–schistosome interactions. By focusing on linkage among genic and nonrepetitive regions, we have generated a useful resource for associating snail phenotypes with causal genes, even in the absence of a complete genome assembly. A similar approach could potentially improve numerous poorly-assembled genomes in other taxa. This map will facilitate future work on this host of a serious human parasite.


Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 517-529
Author(s):  
Kuldeep Singh ◽  
D S Multani ◽  
Gurdev S Khush

Abstract Secondary trisomics and telotrisomics representing the 12 chromosomes of rice were isolated from the progenies of primary trisomics. A large population of each primary trisomic was grown. Plants showing variation in gross morphology compared to the primary trisomics and disomic sibs were selected and analyzed cytologically at diakinesis and pachytene. Secondary trisomics for both arms of chromosomes 1, 2, 6, 7 and 11 and for one arm of chromosomes 4, 5, 8, 9 and 12 were identified. Telotrisomics for short arm of chromosomes 1, 8, 9 and 10 and for long arms of chromosomes 2, 3 and 5 were isolated. These secondary and telotrisomics were characterized morphologically and for breeding behavior. Secondary trisomics 2n + 1S · 1S, 2n + 1L · 1L, 2n + 2S · 2S, 2n + 2L · 2L, 2n + 6S · 6S, 2n + 6L · 6L and 2n + 7L · 7L are highly sterile, and 2n + 1L · 1L, 2n + 2L · 2L and 2n + 7L · 7L do not set any seed even upon backcrossing. Telotrisomics are fertile and vigorous. Genetic segregation of 43 marker genes was studied in the F2 or backcross progenies. On the basis of segregation data, these genes were delimited to specific chromosome arms. Correct orientation of 10 linkage groups was determined and centromere positions on nine linkage groups were approximated. A revised linkage map of rice is presented.


Genetics ◽  
1977 ◽  
Vol 85 (3) ◽  
pp. 417-425
Author(s):  
Carl Frankel ◽  
Albert H Ellingboe

ABSTRACT Forty-eight useful new mutations of S. commune were obtained by mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Their requirements and meiotic linkage relationships to each other and previously mapped areas were investigated. Several of these new mutations were incorporated into diploid strains so that the diploids contained at least one marker on every linkage group. Analysis of somatic recombination in these diploids indicated that each meiotic linkage group corresponded to an independent chromosome.


Genome ◽  
2002 ◽  
Vol 45 (2) ◽  
pp. 282-295 ◽  
Author(s):  
Elizabeth S Jones ◽  
Natalia L Mahoney ◽  
Michael D Hayward ◽  
Ian P Armstead ◽  
J Gilbert Jones ◽  
...  

A molecular-marker linkage map has been constructed for perennial ryegrass (Lolium perenne L.) using a one-way pseudo-testcross population based on the mating of a multiple heterozygous individual with a doubled haploid genotype. RFLP, AFLP, isoenzyme, and EST data from four collaborating laboratories within the International Lolium Genome Initiative were combined to produce an integrated genetic map containing 240 loci covering 811 cM on seven linkage groups. The map contained 124 codominant markers, of which 109 were heterologous anchor RFLP probes from wheat, barley, oat, and rice, allowing comparative relationships between perennial ryegrass and other Poaceae species to be inferred. The genetic maps of perennial ryegrass and the Triticeae cereals are highly conserved in terms of synteny and colinearity. This observation was supported by the general agreement of the syntenic relationships between perennial ryegrass, oat, and rice and those between the Triticeae and these species. A lower level of synteny and colinearity was observed between perennial ryegrass and oat compared with the Triticeae, despite the closer taxonomic affinity between these species. It is proposed that the linkage groups of perennial ryegrass be numbered in accordance with these syntenic relationships, to correspond to the homoeologous groups of the Triticeae cereals.Key words: Lolium perenne, genetic linkage map, RFLP, AFLP, conserved synteny.


1995 ◽  
Vol 66 (2) ◽  
pp. 109-126 ◽  
Author(s):  
Jinrui Shi ◽  
David G. Heckel ◽  
Marian R. Goldsmith

SummaryWe present data for the initial construction of a molecular linkage map for the domesticated silkworm, Bombyx mori, based on 52 progeny from an F2 cross from a pair mating of inbred strains p50 and C108, using restriction fragment length polymorphisms (RFLPs). The map contains 15 characterized single copy sequences, 36 anonymous sequences derived from a follicular cDNA library, and 10 loci corresponding to a low copy number retrotransposon, mag. The 15 linkage groups and 8 ungrouped loci account for 23 of the 28 chromosomes and span a total recombination length of 413 cM; 10 linkage groups were correlated with established classic genetic maps. Scoring data from Southern blots were analysed using two Pascal programs written specifically to analyse linkage data in Lepidoptera, where females are the heterogametic sex and have achiasmatic meiosis (no crossing-over). These first examine evidence for linkage by calculating the maximum lod score under the hypothesis that the two loci are linked over the likelihood under the hypothesis that the two loci assort independently, and then determine multilocus linkage maps for groups of putatively syntenic loci by calculating the maximum likelihood estimate of the recombination fractions and the log likelihood using the EM algorithm for a specified order of loci along the chromosome. In addition, the possibility of spurious linkage was exhaustively tested by searching for genotypes forbidden by the absence of crossing-over in one sex.


2001 ◽  
Vol 31 (8) ◽  
pp. 1456-1461
Author(s):  
M Troggio ◽  
T L Kubisiak ◽  
G Bucci ◽  
P Menozzi

We tested the constancy of linkage relationships of randomly amplified polymorphic DNA (RAPD) marker loci used to construct a population-based consensus map in material from an Italian stand of Picea abies (L.) Karst. in 29 individuals from three Norwegian populations. Thirteen marker loci linked in the Italian stand did show a consistent locus ordering in the Norwegian population. The remaining 16 unlinked marker loci were spread over different linkage groups and (or) too far apart both in the population map and in this study. The limited validity of RAPD markers as genomic "hallmarks" resilient across populations is discussed. We also investigated the reliability of RAPD markers; only 58% of the RAPD markers previously used to construct the consensus map in the Italian population were repeatable in the same material. Of the repeatable ones 76.3% were amplified and found polymorphic in 29 megagametophyte sibships from three Norwegian populations.


Genetics ◽  
2001 ◽  
Vol 157 (3) ◽  
pp. 1369-1385 ◽  
Author(s):  
Z W Luo ◽  
C A Hackett ◽  
J E Bradshaw ◽  
J W McNicol ◽  
D Milbourne

Abstract This article presents methodology for the construction of a linkage map in an autotetraploid species, using either codominant or dominant molecular markers scored on two parents and their full-sib progeny. The steps of the analysis are as follows: identification of parental genotypes from the parental and offspring phenotypes; testing for independent segregation of markers; partition of markers into linkage groups using cluster analysis; maximum-likelihood estimation of the phase, recombination frequency, and LOD score for all pairs of markers in the same linkage group using the EM algorithm; ordering the markers and estimating distances between them; and reconstructing their linkage phases. The information from different marker configurations about the recombination frequency is examined and found to vary considerably, depending on the number of different alleles, the number of alleles shared by the parents, and the phase of the markers. The methods are applied to a simulated data set and to a small set of SSR and AFLP markers scored in a full-sib population of tetraploid potato.


2003 ◽  
Vol 28 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Amaury S. Santos ◽  
Ricardo E. Bressan-Smith ◽  
Messias G. Pereira ◽  
Rosana Rodrigues ◽  
Claudia F. Ferreira

Common bean (Phaseolus vulgaris) cultivars with a high degree of resistance to Xanthomonas axonopodis pv. phaseoli (Xap) are not available in Brazil. Despite many studies, a low degree of resistance to Xap continues to exist due to its complex genetic inheritance, which is not well known. The objectives of this research were to complement a common bean genetic map based on the cross between a susceptible genotype 'HAB-52' and a resistant genotype 'BAC-6', and to map and analyze genomic regions (quantitative trait loci – QTLs) related to Xap resistance. Eleven linkage groups were determined using 143 RAPD markers, covering 1,234.5 cM of the genome. This map was used to detect QTLs associated with Xap resistance on leaves and pods. The averages of disease severity on leaves (represented by the transformed disease index – TDI) and pods (represented by the diameter of lesion on pods – DLP) were added to the data of the linkage map. Five TDI QTLs and only one LDP QTL were detected. The TDI QTLs were placed in the A, B, G and J linkage groups, with phenotypic variations ranging from 12.7 to 71.6%. The DLP QTL explained 12.9% of the phenotypic variation and was mapped in a distinct linkage group. These results indicate that there are different genes involved in the control of resistance on leaves and pods.


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